Diaphragm valves using solenoid-operated pilots are known. Such a valve is described, for example, in U.S. Pat. No. 3,410,310, which issued Nov. 12, 1968, and which is assigned to the present assignee. In the prior art pilot-operated diaphragm valves, the pressure drop between the inlet and outlet of the valve is the determining factor in the position of the diaphragm. However, at lower flow rates, minimal differential pressure is exerted on the diaphragm, and the diaphragm has a tendency to modulate which produces instability in the system. The valve assembly of the present invention is constructed so that even at the low flow rates through the valve, a substantial pressure differential is established across the diaphragm, in order that stable operation is achieved at all times.